Typically in chemical research and development activities, it is being practiced to dissolve various materials into inorganic or organic solvents to make solutions and effect analyses using such solutions, and hence it is necessary to prepare various many solutions. Under the circumstances, there has been a demand for automatizing analytic systems in order to win the competition among researchers and developers by simply and quickly carrying out analytic processes.
In such analytic processes, materials to be analyzed and solvents are poured into a number of containers such as measuring flasks to prepare target amounts of solutions and hold them in the containers. A target amount of solution cannot be obtained simply by dissolving a certain amount of material into a certain amount of solvent. Therefore, it is necessary to perform a filling process for holding a target amount of solution in a container.
Since the filling process is difficult to automatize, however, it is difficult to fully automatize an analytic system in its entirety.
The filling process is a process for filling a solution up to a line called a marked line on a container under certain conditions. An error of the filling process depends on how the level of the solution in the container deviates from the marked line. The filling process is an important task which eventually determines the value of a series of analytic operations. Consequently, the filling process needs to be carried out strictly, and hence is a process which the person in charge has to be most careful about among various analytic operations and which cannot be neglected.
The above strict requirements for the filling process have been one of various factors which have made it difficult to automatize the filling process. The filling process that need delicate adjustments has imposed burdens with respect to time and labor on those involved in the filling process.
Another factor is that the conventional detecting technology is not available for automatically detecting a marked line on containers and automatically detecting solution levels in containers with high accuracy. According to the conventional detecting technology, a level sensor or a float switch is used to detect a solution level from above or detect a solution level in direct contact with the solution. Though these detecting processes have been studied so far, they have proven unsatisfactory as they are not preferable from the standpoint of the filling process.
In view of the conventional drawbacks, it has been proposed to optically detect a marked line and a solution level (including its meniscus) with a laser beam, for example, and carry out a filling process using a detected signal.
Apparatus which use a laser beam to detect a marked line and a meniscus are expected to suffer various detection interferences depending on how to process actual samples. Specifically, the solution sample in a container when it is filled in the container tends to a) become turbid, b) produce bubbles, and c) become attached to the container wall in pretreating operations. Since these defects are an obstacle to the transmission of detected light of the laser beam, i.e., irregularly reflect or block such detected light, they are liable to interfere with the detection of the marked line and the meniscus. As a result, the accuracy with which the marked line and the meniscus are detected is low, and hence the accuracy of the filling process is not highly reliable.
Proposals for eliminating these interferences have been to A) keep the solution clear by centrifugal separation and filtering, B) remove bubbles from the solution with a debubblizer such as alcohol or the like, and C) clean the inner surface of the container with a solvent.
These processes A).about.C) have to be carried out with respect to many containers when various many solutions are to be prepared. The processes B) and C) have heretofore been carried out manually, and hence pretreating operations for analyses have been inefficient and imposed strong burdens with respect to time and labor. At present, it is difficult to automatize and effect these pretreating processes continuously.